Patients between 18 and 65 years of age with early osteoarthritis and degenerative chondropathy who had previously taken medication for more than six months and without physical improvement, were assessed in an open clinical trial. The 44 patients who met the experiment criteria and who voluntarily gave written consent to PRP treatment, were finally selected. The knee joint had to be stable and without a severe deformity greater than 5 degrees in the valgus or varus.